1. Technical Field
The present disclosure relates to a method for forming a crystal nucleus in a latent heat storage material and a heat storage device.
2. Description of the Related Art
In the past, a study of a latent heat storage material using latent heat which is accumulated when the latent heat storage material changes from a solid phase to a liquid phase and is released when the latent heat storage material changes from the liquid phase to the solid phase has been conducted.
For example, in Japanese Patent No. 3588630, as depicted in FIG. 13, a heat storage type heater body 700 using a heat storage material 701 which can be supercooled is described. The heat storage type heater body 700 includes the heat storage material 701, a container 702, a heat exchanger 704, an outer frame 705, and a thermoelectric element 706. The container 702 is a container to be filled with the heat storage material 701. The heat exchanger 704 is a heat exchanger for supplying heat to the heat storage type heater body 700. The heat from the heat storage type heater body 700 is released by using the outer frame 705 as a radiating surface.
The thermoelectric element 706 is a means for terminating the supercooled state of the heat storage material 701, and, when a voltage is applied to the thermoelectric element 706, part of the thermoelectric element 706, the part located on the side thereof where the heat storage material 701 is located, is cooled. When the temperature of part of the heat storage material 701 reaches a temperature at which a crystal nucleus is formed in a supercooled state, a crystal nucleus is formed. The formation of the crystal nucleus triggers the solidification of the heat storage material 701, and heat with a temperature at the melting point of the heat storage material 701 is released.
Japanese Patent No. 3588630 includes the description of the use of a piezoelectric element, an agitator such as an electric vibrator, a pipe through which a low-temperature fluid passes, or an electrode in place of the thermoelectric element 706 as the means for terminating the supercooling state of the heat storage material 701. If the pipe through which the low-temperature fluid passes is used as the means for terminating the supercooling state of the heat storage material 701, the formation of a crystal nucleus is caused by the low-temperature fluid, temperature of which is lower than a temperature at which the heat storage material 701 forms a crystal nucleus in a supercooled state. If the agitator is used as the means for terminating the supercooling state of the heat storage material 701, the positions of some of the molecules of the heat storage material 701 are forcefully changed by the agitator from the outside, whereby the crystallization of the heat storage material 701 is induced. If the electrode is used as the means for terminating the supercooling state of the heat storage material 701, an electric force is applied to part of the heat storage material 701 by the application of a voltage from the outside, whereby a molecular cluster which is greater than or equal to the radius of a critical nucleus is formed. In Japanese Patent No. 3588630, a technique of inducing the crystallization of the heat storage material 701 by forcefully changing the positions of the molecules of the heat storage material 701 from the outside by spark discharge is also disclosed.